The world’s newest, largest and most complicated telescope is now officially open for astronomy. Located high in the deserts of Chile, the European Southern Observatory’s Atacama Large Millimetre/sub-millimetre Array (ALMA) is made up of a series of interlinked antennas stretching across an ultra-arid plain 5,000m (~16,400ft) above sea level. Such conditions – and the array’s clever technology – allow it to observe light never before seen by the human eye, which will provide humans with the ability to peer into distant gas clouds, swirling cosmic dust and even the supermassive black hole at the center of our galaxy.
So far, only 20 of the 66 planned antennas are operational, but ALMA’s first image, clouds of dense cold gas in the colliding Antennae Galaxies (aka NGC 4038 and 4039) 70 million light-years away, shows what the telescope is capable of. The image was created with just 12 antennas, which are built at a separate location then transported nearly 20 miles to the site in the remote Chajnantor plateau on special crawlers equipped with oxygen for the drivers.
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“ALMA is an awe-inspiring piece of engineering,” says John Richer, a project scientist with ALMA UK. “Every aspect of it is state-of-the-art. For example, the antennas use innovative carbon fibre designs to keep their shapes precise to only a few microns, less than the width or a human hair, even in hostile weather conditions. The superconducting receivers have to amplify very high-frequency radio signals without adding too much noise. The central correlation computer has to process vast volumes of digital data from the receivers, a data rate that exceeds total internet traffic of the UK. And finally this all has to be done on a very remote site, deprived of oxygen due to its [incredible] altitude.”
The construction of ALMA got underway in 2003, after a bunch of countries from North America, Europe and Asia got together to combine their planned arrays into one single giant one. Each international partner is supplying a percentage of the antennas, and each is hoping to study different things. Japan, for instance, will be looking at Himiko – a ‘massive and mysterious gas blob’ discovered in 2009. The Dutch, meanwhile, are keen to peer into Sagittarius A* – the supermassive black hole at the center of the Milky Way which is normally obscured by gas and dust.
“ALMA will let us watch flares of light coming from around this supermassive black hole,” explains Heino Falcke, an astronomer at Radboud University Nijmegen in the Netherlands, “and make images of the gas clouds caught by its immense pull. This will let us study this monster’s messy feeding habits. We think that some of the gas may be escaping its grip, at close to the speed of light.”
Building the array has been a difficult and expensive process, with the overall cost expected to exceed a billion US dollars, but by 2013 the telescope will offer an unprecedented nearly 10 mile-wide array with which to observe the remote – and therefore early – universe. When it’s joined next decade by the Extremely Large Telescope, Chile will have, according to the BBC, ‘more than half the image-capturing capacity in the world’.
“Projects like ALMA require an enormous amount of patience,” concludes Gary Fuller of the UK ALMA Regional Center Node at The University of Manchester. “Many of us have been working on this for more than a decade. There have been many obstacles to be overcome, but I’ve no doubt that it will all be worth it – it’s great to see the first scientific observations beginning for astronomers from the UK and around the world.”
By Chris Hatherill
Connections:
- The Largest Telescope on Earth
- There’s Life in the Cosmos, Just Not the Will To Find It
- The Astronomy Motherboard
For more, check out Super/Collider.
